/*
 * Copyright (c) 2016-2088, fastquery.org and/or its affiliates. All rights reserved.
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * For more information, please see http://www.fastquery.org/.
 *
 */

package org.fastquery.core;

import java.io.BufferedReader;
import java.io.FileReader;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.*;
import java.util.function.BiConsumer;
import java.util.regex.Pattern;
import java.util.stream.Stream;
import java.util.stream.Stream.Builder;

import com.alibaba.fastjson.JSONArray;
import lombok.AccessLevel;
import lombok.NoArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.RegExUtils;
import org.apache.commons.lang3.StringUtils;
import org.fastquery.util.TypeUtil;
import org.fastquery.struct.RespUpdate;
import org.fastquery.struct.SQLValue;
import org.fastquery.util.BeanUtil;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;

/**
 * DB 最基本操作
 *
 * @author mei.sir@aliyun.cn
 */
@Slf4j
@NoArgsConstructor(access = AccessLevel.PRIVATE)
public class DB
{
    private static void statSetObject(PreparedStatement stat, int parameterIndex, Object object) throws SQLException
    {
        if (object instanceof Enum)
        {
            Enum<?> e = (Enum<?>) object;
            int index = e.ordinal() + 1; // 数据库中枚举元素对应的数字索引
            stat.setObject(parameterIndex, index);
        }
        else if(object instanceof JSON)
        {
            stat.setObject(parameterIndex, object.toString());
        }
        else
        {
            stat.setObject(parameterIndex, object);
        }
    }

    public static List<Map<String, Object>> find(SQLValue sqlValue)
    {
        String sql = sqlValue.getSql();
        List<Object> objs = sqlValue.getValues();
        List<Map<String, Object>> keyvals;
        Connection conn = QueryContext.getConn();
        PreparedStatement stat = null;
        ResultSet rs = null;
        try
        {
            QueryContext.addSqls(sql);
            info(sql, objs);
            stat = conn.prepareStatement(sql);
            // 设置sql参数值
            int lenTmp = objs.size(); // objs 源头上已经控制禁止为null
            for (int i = 0; i < lenTmp; i++)
            {
                statSetObject(stat, i + 1, objs.get(i));
            }
            // 设置sql参数值 End
            rs = stat.executeQuery();
            keyvals = rs2Map(rs);
            stat.close();
        }
        catch (Exception e)
        {
            throw new RepositoryException(e.getMessage(), e);
        }
        finally
        {
            close(rs, stat);
        }

        return keyvals;
    }

    /**
     * @param sqlValues 待执行的SQL集
     * @param hasPK     是否需要返回主健
     * @return 改操作响应数据
     */
    static List<RespUpdate> modify(List<SQLValue> sqlValues, boolean hasPK)
    {
        List<RespUpdate> rus;
        Connection conn = QueryContext.getConn(); // 由QueryContext自动关闭
        try
        {
            QueryContext.disableAutoCommit(); // 关闭自动提交
            rus = modify(sqlValues, hasPK, conn);
            QueryContext.commit(); // 提交事务
        }
        catch (Exception e)
        {
            try
            {
                QueryContext.rollback();
            }
            catch (SQLException e1)
            {
                throw new RepositoryException(e1.getMessage(), e1);
            }
            throw new RepositoryException(e.getMessage(), e);
        }

        return rus;
    }

    private static List<RespUpdate> modify(List<SQLValue> sqlValues, boolean hasPK, Connection conn) throws SQLException
    {
        List<RespUpdate> rus = new ArrayList<>();
        for (SQLValue sqlValue : sqlValues)
        {
            ResultSet rs = null;
            PreparedStatement stat = null;
            RespUpdate ru = new RespUpdate();
            try
            {
                String sql = sqlValue.getSql();
                QueryContext.addSqls(sql);
                info(sql, sqlValue.getValues());
                if (hasPK)
                {
                    stat = conn.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS);
                }
                else
                {
                    stat = conn.prepareStatement(sql);
                }
                List<Object> values = sqlValue.getValues();
                int len = values.size();
                for (int i = 0; i < len; i++)
                {
                    // 设置sql参数值
                    statSetObject(stat, i + 1, values.get(i));
                }

                ru.setEffect(stat.executeUpdate());

                if (hasPK)
                {
                    rs = stat.getGeneratedKeys();
                    if (rs.next())
                    {
                        ru.setPk(rs.getLong(1));
                    }
                }
                stat.close();
            }
            catch (SQLException e)
            {
                throw new SQLException(e);
            }
            finally
            {
                close(rs, stat);
            }

            rus.add(ru);
        }

        return rus;
    }

    /**
     * 改操作,若:isEffect=true,返回影响行数;若:isEffect=false,返回主键值.
     *
     * @param sql      语句
     * @param isEffect 是否返回影响行数
     * @return 影响行数 或 主键值
     */
    static Object update(String sql, boolean isEffect)
    {
        Connection conn = null;
        PreparedStatement stat = null;
        ResultSet rs = null;
        Object key = null;
        try
        {
            conn = QueryContext.getConn();
            QueryContext.addSqls(sql);
            QueryContext.disableAutoCommit();
            log.info(sql);
            if (isEffect)
            {
                stat = conn.prepareStatement(sql); // 不需要返回主键
            }
            else
            {
                stat = conn.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS);
            }
            int e = stat.executeUpdate();
            if (isEffect)
            {
                QueryContext.commit();
                return e;
            }
            else
            {
                rs = stat.getGeneratedKeys();
                // 获取主键
                if (rs.next())
                {
                    key = rs.getObject(1);
                }
                QueryContext.commit();
                return key;
            }
        }
        catch (SQLException e)
        {
            if (conn != null)
            {
                try
                {
                    QueryContext.rollback();
                }
                catch (SQLException e1)
                {
                    throw new RepositoryException(e1);
                }
            }
            throw new RepositoryException(e);
        }
        finally
        {
            close(rs, stat);
        }
    }

    static int update(Object bean, String dbName, String where)
    {
        Connection conn = null;
        PreparedStatement stat = null;
        Object[] updateInfo = (where == null || StringUtils.EMPTY.equals(where)) ? BeanUtil.toUpdateSQL(bean, dbName, false)
                : BeanUtil.toUpdateSQL(bean, dbName, where);
        if (updateInfo == null || updateInfo.length == 0)
        {
            return 0;
        }
        String sql = updateInfo[0].toString();
        log.info(sql);
        @SuppressWarnings("unchecked")
        List<Object> args = (List<Object>) updateInfo[1];
        int count = args.size();
        int effect;
        try
        {
            conn = QueryContext.getConn();
            QueryContext.disableAutoCommit();
            QueryContext.addSqls(sql);
            info(sql, args);
            stat = conn.prepareStatement(sql);
            for (int i = 1; i <= count; i++)
            {
                statSetObject(stat, i, args.get(i - 1));
            }
            effect = stat.executeUpdate();
            QueryContext.commit();
        }
        catch (SQLException e)
        {
            if (conn != null)
            {
                try
                {
                    QueryContext.rollback();
                }
                catch (SQLException e1)
                {
                    throw new RepositoryException(e1);
                }
            }
            throw new RepositoryException(e);
        }
        finally
        {
            close(null, stat);
        }
        return effect;
    }

    // 查询一条数据然后转换成一个实体
    static Object select(String sql, Object bean)
    {
        Class<?> cls = (bean instanceof Class) ? (Class<?>) bean : bean.getClass();
        Connection conn;
        Statement stat = null;
        ResultSet rs = null;
        try
        {
            conn = QueryContext.getConn();
            stat = conn.createStatement();
            log.info(sql);
            QueryContext.addSqls(sql);
            rs = stat.executeQuery(sql);
            List<Map<String, Object>> maps = rs2Map(rs);
            if (maps.isEmpty())
            {
                return null;
            }
            //return JSON.toJavaObject(new JSONObject(maps.get(0)), cls)
            return TypeUtil.map2Obj(cls, maps.get(0));
        }
        catch (Exception e)
        {
            throw new RepositoryException(e);
        }
        finally
        {
            close(rs, stat);
        }
    }

    static boolean exists(String sql)
    {
        Connection conn;
        Statement stat = null;
        ResultSet rs = null;
        try
        {
            conn = QueryContext.getConn();
            stat = conn.createStatement();
            QueryContext.addSqls(sql);
            rs = stat.executeQuery(sql);
            return rs.next();
        }
        catch (SQLException e)
        {
            throw new RepositoryException(e);
        }
        finally
        {
            close(rs, stat);
        }
    }

    public static boolean exists(SQLValue sqlValue)
    {
        String sql = sqlValue.getSql();
        List<Object> objs = sqlValue.getValues();
        Connection conn = QueryContext.getConn();
        PreparedStatement stat = null;
        ResultSet rs = null;
        try
        {
            QueryContext.addSqls(sql);
            info(sql, objs);
            stat = conn.prepareStatement(sql);
            // 设置sql参数值
            int lenTmp = objs.size(); // objs 源头上已经控制禁止为null
            for (int i = 0; i < lenTmp; i++)
            {
                statSetObject(stat, i + 1, objs.get(i));
            }
            // 设置sql参数值 End
            rs = stat.executeQuery();
            return rs.next();
        }
        catch (Exception e)
        {
            throw new RepositoryException(e.getMessage(), e);
        }
        finally
        {
            close(rs, stat);
        }
    }

    private static Stream<String> parserSQLFile(String name)
    {
        Builder<String> builder = Stream.builder();

        try (FileReader reader = new FileReader(name); BufferedReader br = new BufferedReader(reader))
        {
            StringBuilder buff = new StringBuilder();
            String str;
            while ((str = br.readLine()) != null)
            {
                str = str.trim();
                if (!StringUtils.EMPTY.startsWith(str) && !str.startsWith("#") && !str.startsWith("--"))
                {
                    buff.append(str);
                    buff.append(' ');
                    int index = buff.indexOf(";");
                    if (index != -1)
                    {
                        builder.add(buff.substring(0, index).trim());
                        buff.delete(0, index + 1);
                    }
                }
            }

            String lastStr = buff.toString().trim();
            if (!StringUtils.EMPTY.equals(lastStr))
            {
                builder.add(lastStr);
            }

        }
        catch (Exception e)
        {
            throw new RepositoryException(e);
        }

        return builder.build();
    }

    static int[] executeBatch(String sqlFile, String[] quotes, BiConsumer<Statement, String> consumer)
    {
        Connection conn = QueryContext.getConn();
        Statement stat = null;
        Stream<String> stream = parserSQLFile(sqlFile);
        try
        {
            QueryContext.disableAutoCommit();
            final Statement st = conn.createStatement();
            stat = st;
            stream.forEach(s -> {
                if (quotes != null)
                {
                    int len = quotes.length;
                    for (int i = 0; i < len; i++)
                    {
                        String val = quotes[i];
                        if (val == null)
                        {
                            val = StringUtils.EMPTY;
                        }
                        Pattern p = RegexCache.getPattern("\\$\\[" + i + "]");
                        s = RegExUtils.replaceAll(s,p,val);
                    }
                }
                consumer.accept(st, s);
            });
            int[] ints = stat.executeBatch();
            stat.clearBatch();
            QueryContext.commit();
            return ints;
        }
        catch (Exception e)
        {
            try
            {
                QueryContext.rollback();
            }
            catch (SQLException e1)
            {
                throw new RepositoryException(e1.getMessage(), e1);
            }
            throw new RepositoryException(e);
        }
        finally
        {
            close(null, stat);
        }
    }

    /**
     * 释放资源
     *
     * @param rs   ResultSet实例
     * @param stat Statement实例
     */
    private static void close(ResultSet rs, Statement stat)
    {
        try
        {
            if (rs != null)
            {
                rs.close();
            }
        }
        catch (SQLException e)
        {
            throw new RepositoryException(e);
        }
        finally
        {
            try
            {
                if (stat != null)
                {
                    stat.close();
                }
            }
            catch (SQLException e)
            {
                log.error(e.getMessage(), e);
            }
        }
    }

    /**
     * 将 rs 的结果集 转换成 List&lt;Map&gt;,rs没有结果则返回空对象(该方法永不返回null).
     *
     * @param rs 结果集
     * @return List map结果集
     * @throws SQLException SQL异常
     */
    private static List<Map<String, Object>> rs2Map(ResultSet rs) throws SQLException
    {

        List<Map<String, Object>> keyvals = new ArrayList<>();
        Map<String, Object> keyval;
        // 获取列信息
        ResultSetMetaData resultSetMetaData;
        // 总列数
        int columnCount;

        String key;
        Object obj;
        while (rs.next())
        {
            resultSetMetaData = rs.getMetaData();
            columnCount = resultSetMetaData.getColumnCount();
            keyval = new HashMap<>();
            for (int i = 1; i <= columnCount; i++)
            {
                key = resultSetMetaData.getColumnLabel(i); // 获取列别名,若没有别名那么就获取本身名称(getColumnName)
                obj = rs.getObject(i);
                String columnType = resultSetMetaData.getColumnTypeName(i);
                if("JSON".equals(columnType))
                {
                    if(obj == null || "null".equals(obj))
                    {
                        String columnName = resultSetMetaData.getColumnName(i);
                        if(columnName.endsWith("Obj"))
                        {
                            obj = new JSONObject();
                        }
                        else if(columnName.endsWith("Array"))
                        {
                            obj = new JSONArray();
                        }
                    }
                    else
                    {
                        obj = JSON.parse(obj.toString());
                    }
                }
                keyval.put(key, obj);
            }
            keyvals.add(keyval);
        }
        return keyvals;
    }

    /**
     * 输出执行日志
     *
     * @param sql  sql语句
     * @param objs 参数
     */
    private static void info(String sql, List<Object> objs)
    {
        if (log.isInfoEnabled())
        { // 这个输出要做很多事情,在此判断一下很有必要,生产环境通常是warn级别
            StringBuilder sb = new StringBuilder("\n正在准备执行SQL:");
            sb.append(sql);
            sb.append(StringUtils.LF);
            if (objs != null && !objs.isEmpty())
            {
                int len = objs.size();
                for (int i = 0; i < len; i++)
                {
                    sb.append(String.format("第%d个\"?\"对应的参数值是:%s;%n", i + 1, objs.get(i)));
                }
            }
            log.info(sb.toString());
        }
    }
}
